Evaluation of shear bond strength between PEEK and resin-based luting material

Objectives

The purpose of this study was to evaluate the bond strength of polyetheretherketone (PEEK) to resin-based luting material.

止血剂对乳牙牙本质黏结强度的影响

目的:探讨止血剂对乳牙牙本质黏结强度的影响.方法:选取40颗滞留乳磨牙,构建磨切后牙本质模型,随机分为观察组和对照组,每组20颗实验牙.观察组采用止血剂覆盖30 s后冲洗,然后进行黏结处理,对照组直接进行黏结处理.观察2组微拉伸黏结强度、微渗漏情况.采用SPSS 19.0软件包对数据进行统计学分析.结果:观察组微拉伸黏结强度为(12.84±2.10)MPa,显著低于对照组的(14.03±2.28)MPa(P＜0.05);观察组形成的树脂突大部分＞35 μm,且长而密集,伸入开放的牙本质小管中;对照组形成的树脂突长约7～35 μm,侧支交通明显;2组牙本质黏结剂的微渗漏程度比例差异无显著性(P＞0.05).结论:止血剂对乳牙牙本质黏结强度有一定影响,临床应用时应特别注意.     

不同粘接剂对烤瓷瓷面与金属托槽间剪切强度影响的体外研究

目的 研究不同粘接剂对烤瓷瓷面与金属托槽间剪切强度的影响.方法 40个烤瓷瓷面经打磨、氢氟酸酸蚀、冲洗干燥、硅烷偶联剂处理瓷面后,再根据使用粘接剂的不同分为A组:光固化复合树脂粘接剂、B组:单组份化学固化复合树脂粘接剂、C组:树脂改良型光固化玻璃离子粘接剂、D组:双组份化学固化复合树脂粘接剂.将40个金属托槽粘接于烤瓷瓷面,经水浴孵化24 h后测得样本剪切强度,并进行统计分析.结果 A组剪切强度大于其他组(P＜0.05),C组剪切强度小于B组(P＜0.05),D组与B、C组剪切强度差异无统计学意义(P＞0.05).结论 光固化复合树脂粘接剂可获得最大的剪切强度,树脂改良型光固化玻璃离子粘接剂对金属托槽与烤瓷瓷面的粘接效果欠佳.     

Analysis of the Optimum Usage of Slag for the Compressive Strength of Concrete

Ground granulated blast furnace slag is widely used as a mineral admixture to replace partial Portland cement in the concrete industry. As the amount of slag increases, the late-age compressive strength of concrete mixtures increases. However, after an optimum point, any further increase in slag does not improve the late-age compressive strength. This optimum replacement ratio of slag is a crucial factor for its efficient use in the concrete industry. This paper proposes a numerical procedure to analyze the optimum usage of slag for the compressive strength of concrete. This numerical procedure starts with a blended hydration model that simulates cement hydration, slag reaction, and interactions between cement hydration and slag reaction. The amount of calcium silicate hydrate (CSH) is calculated considering the contributions from cement hydration and slag reaction. Then, by using the CSH contents, the compressive strength of the slag-blended concrete is evaluated. Finally, based on the parameter analysis of the compressive strength development of concrete with different slag inclusions, the optimum usage of slag in concrete mixtures is determined to be approximately 40% of the total binder content. The proposed model is verified through experimental results of the compressive strength of slag-blended concrete with different water-to-binder ratios and different slag inclusions.     

Efficacy of a simple and inexpensive exercise training program for advanced chronic obstructive pulmonary disease patients in community hospitals

Background

Exercise training is an important part of pulmonary rehabilitation; however it may not be appropriate for large-scale practice in community hospitals due to the complexity of the program and expensive training equipment, including cycle ergometry and treadmills. This study therefore aims to evaluate the efficacy of a more simplified exercise training program with inexpensive training equipment.

Methods

A multicentre study of a mild to moderate intensity exercise training program was conducted based on incremental strength and endurance with two 35-40-minute sessions per week for 8 weeks. The program was performed by 30 outpatients from five community hospitals. Patients were monitored regularly for various parameters including strength of trained muscles, level of dyspnea, 6-minute walk distance, and quality of life (QoL) at baseline at 1, 2, 3, 6, 9 and 12 months. Unpaired t-tests were applied to determine the progress of trained muscle strength and minimal clinically important differences (MCIDs) were used to assess clinical outcomes.

Results

Thirty patients (13 males, 17 females) were enrolled with a mean age of 69.1±8.9 years, body mass index 20.5±4.4 kg/m², and mean % of predicted forced expiratory volume in the first second (FEV₁) 45.1±10.8. According to GOLD classification, eight (26.7%) cases were in stage II, 20 (66.7%) cases in stage III, and two (6.6%) cases in stage IV. Limb and chest wall muscle strength, dyspnea level, exercise capacity and QoL showed statistically significant improvements throughout the 12-month follow-up (P<0.01). There were clinically significant improvements in QoL throughout the 12-month follow-up, exercise capacity from months 2 to 12, and dyspnea levels at months 2, 3 and 9.

Conclusions

The implementation of a simplified and inexpensive exercise training program was shown to be effective for advanced chronic obstructive pulmonary disease patients in community hospitals.     

Comparison of Different Techniques of Ultrasound-Guided Fine Needle Biopsy of Liver in a Swine Model

Background:

The quality of liver biopsy specimens obtained with different fine needle biopsy (FNB) techniques has not been compared.

Objectives:

This study was performed to evaluate the diagnostic quality of three different liver FNB biopsy techniques.

Materials and Methods:

Two sequential biopsy series were performed on piglets. Three biopsy techniques were compared: capillary-FNB, core-FNB (CFNB) and vacuum-assisted CFNB (VACFNB) in a swine model. Initially, 30 liver biopsies were performed (ten for each technique). The cellularity and quantity of blood in specimens were measured and compared. In the second series, 54 additional biopsies using CFNB and VACFNB techniques (27 each) in a separate piglet were evaluated in the same fashion.

Results:

In the first series, cellularity and blood levels were significantly lower in capillary-FNB compared with CFNB (P < 0.001 and P = 0.011, respectively). There was no significant difference between CFNB and VACFNB in cellularity and blood (P = 0.15 and P = 0.1, respectively). In the second series, cellularity was significantly higher in CFNB compared with VACFNB (P < 0.001) with no significant difference in blood (P = 0.5).

Conclusions:

Among these three different FNB techniques, CFNB technique provided the greatest cellularity. Capillary-FNB technique was inferior among all with the lowest quality of obtained material for cytopathological interpretation.     

Hepatitis C virus core antigen: A simplified treatment monitoring tool,including for post-treatment relapse

BackgroundSimple, affordable diagnostic tools are essential to facilitate global hepatitis C virus (HCV) elimination efforts.ObjectivesThis study evaluated the clinical performance of core antigen (HCVcAg) assay from plasma samples to monitor HCV treatment efficacy and HCV viral recurrence.Study designPlasma samples from a study of response-guided pegylated-interferon/ribavirin therapy for people who inject drugs with chronic HCV genotype 2/3 infection were assessed for HCV RNA (AmpliPrep/COBAS Taqman assay, Roche) and HCVcAg (ARCHITECT HCV Ag, Abbott Diagnostics) during and after therapy. The sensitivity and specificity of the HCVcAg assay was compared to the HCV RNA assay (gold standard).ResultsA total of 335 samples from 92 enrolled participants were assessed (mean 4 time-points per participant). At baseline, end of treatment response (ETR) and sustained virological response (SVR) visits, the sensitivity of the HCVcAg assay with quantifiable HCV RNA threshold was 94% (95% CI: 88%, 98%), 56% (21%, 86%) and 100%, respectively. The specificity was between 98 to 100% for all time-points assessed. HCVcAg accurately detected all six participants with viral recurrence, demonstrating 100% sensitivity and specificity. One participant with detectable (non-quantifiable) HCV RNA and non-reactive HCVcAg at SVR12 subsequently cleared HCV RNA at SVR24.ConclusionsHCVcAg demonstrated high sensitivity and specificity for detection of pre-treatment and post-treatment viraemia. This study indicates that confirmation of active HCV infection, including recurrent viraemia, by HCVcAg is possible. Reduced on-treatment sensitivity of HCVcAg may be a clinical advantage given the moves toward simplification of monitoring schedules.     

Tannin-based adhesive for protection of colonic anastomosis in the open abdomen

This study was aimed to evaluate the effect of tannin acid- polyethylene glycol (TP) adhesive on the wound healing process of primary colonic anastomosis in the open abdomen (OA). Adhesion strength test, degradation and hemostatic ability of TP were investigated. In a rat model, after standard colonic anastomoses, rats were divided into three groups: OA group; OA + FG (fibrin glue) group; OA + TP group. Five days after surgery, body weight, anastomotic bursting pressure (ABP), and histology of anastomotic tissue were evaluated. Performance of adhesion strength and hemostatic ability of TP was better than that of FG. The weight of TP decreased by over 50% after 11-day incubation. All rats survived well after surgery. Compared to OA group and OA + FG group, OA + TP group showed a significant improvement in body weight, ABP and healing state. Application of TP adhesive, used as an auxiliary treatment of colonic anastomosis operation, improved the wound strength and promoted the anastomotic healing after OA.